This invention relates to the isolation of a nucleic acid sequence that encodes an enzyme capable of removing carboxyl groups from aromatic rings. In particular the enzyme decarboxylates 2,3-dihydroxybenzoic acid to form catechol.
The decarboxylation reaction involves the non-oxidative removal of a carboxyl group from an aromatic ring. Aromatic rings containing a carboxyl group are chemically challenging to work with because the carboxyl group is a deactivating group. Deactivating groups make electrophilic substitutions on aromatic rings difficult. Therefore, the removal of a deactivating carboxyl group from an aromatic ring has a great deal of potential in the chemical industry.
Catechol is an aromatic compound utilized in the development of pharmaceuticals such as L-DOPA(L-3,4-dihydroxyphenylalanine) and adrenaline, agrobiochemicals such as carbofuran, and antioxidants such as 4-tert-butyl catechol and veratrol. Additionally, catechol is utilized in the production of flavorants such as vanilla and polymerization inhibitors. The current global noncaptive market for catechol is 20.5.times.10.sup.6 Kg/yr.
Current commercial production of aromatics has several drawbacks. One disadvantage relates to the starting material utilized in aromatic production. Most aromatics are synthesized from benzene, toluene and xylene which are derived from petroleum or natural gas fossil fuel feedstocks. For example, catechol is currently produced by distillation of coal tar or the hydroxylation of phenol. Both of these methods require fossil fuels as starting material. Fossil fuels are nonrenewable and therefore more expensive than renewable resources. In addition, many countries do not have a large national supply of fossil fuels for the derivation of aromatic compounds.
In addition to cost, the use of fossil fuels has a negative impact on the environment. Petroleum based processes for the production of aromatics often require hazardous starting materials. One example of a hazardous starting material is benzene, which is a carcinogen. These processes also produce hazardous waste by-products that can inadvertently leak into the environment Hazardous waste by-products also need to be disposed of or stored, adding to the costs of operation.
Another problem with current aromatic compound production is that the synthetic procedures involve harsh reaction conditions. Current methods for the removal of carboxyl groups from aromatic rings involve high temperatures and acid conditions in the presence of metal catalysts. These extreme reaction conditions are expensive energy consuming procedures that pose industrial and environmental safety concerns and dramatically increase the cost of the aromatics.
Therefore, a method for the production of aromatics, and specifically catechol, is needed to overcome the problems associated with current methods utilized in the production of aromatics.